Poppet valve with wear resistant stem tip



Dec. 23, 1958 J. A. NEWTON ETAL 2,865,359

POPPET VALVE WITH WEAR RESISTANT STEM TIP Filed May 18. 1955 EM 3% a ammmk u POPPET VALVE WITH WEAR RESISTANT STEM TIP John A. Newton,Painesville, and Max J. Tauschek, Lyndiiurst, Ohio, assignors toThompson Products, Inc, Cleveland, Ohio, acorporation of OhioApplication May 18, 1955, Serial No. 509,312

2 Claims. (Cl. 123-488) This invention relates to a valve with a tippedstern and method of forming the same and more particularly to a valvehaving the impact end of its stem recessed and providedwith an impactnubbin fused to the stem in the recess.

In the manufacture of automobile valves of alloy metal it has been thepractice to provide the impact end of the valve stem with a tip ornubbin of harder metal than that of the stem so as to increase thewearing ability or longevity of the valve in use.

Heretofore, the tip or nubbin has been simply welded on the fiat surfaceat the end of the stem. This practice has been especially followed inthe manufacture of aircraft valves. It has been found, however, thatsuch welded tips resulted in a high rate of manufactured rejects due tocracks and inadequate bonding of the tip to the stem.

An object, therefore, of this invention is to provide an improved impacttip for a valve stem which lends itself to economical manufacture on alarge production scale. I Still another object of the invention is toprovide a simple'but inexpensive method of more-effectively fusing a tipor nubbin to the valve stem so that such tip is actually embodied as anend insert substantially within the confines of the length of the stem.

Yet another object of this invention is to provide a valve stem impacttip of improved metallic composition which will better stand up at thewear point of the end of the stem.

In accordance with the general features of this invention, there isprovided an article of manufacture comprising a valve having a valvestem provided at its impact end with a dished recess and an insertnubbin in the recess of a metal alloy of harder characteristic than thatof the stem bonded to the stem so as to be integral therewith.

In accordance with other features of the invention, there is provided ina method of forming the impact end of a metallic valve stem with animpact tip of harder metal than that of the stem, the steps of providingthe valve end with a dished recess, puddling a molten metal alloy ofharder characteristic than that of the stem in the recess and fusing thepuddled metal to the stem to provide it with an integral tip.

Another feature of the invention relates to the striating or laminatingof the valve stem tip or insert.

Other objects and features of the invention will more.

fully appear from the following detailed description taken in connectionwith the accompanying drawings which illustrate several embodimentsthereof, and in which:

Figure 1 is a fragmentary view of a rocker arm and valve assembly with avalve embodying this invention;

Figure 2 is a fragmentary vertical sectional view through a valve stemhaving a tip with the features of this invention; and

Figure 3 is a view similar to Fig. 2 showing a striated or laminatedinsert.

2,865,359 Patented Dec. 23, I958 As shown on the drawings:

It is believed that this invention will be best understood by firstdescribing a valve assembly of the type used in automobile and aircraftengines to which the valve made pursuant to the presentmethod can beused. In Fig. 1, it will be perceived that a conventional rocker arm isdesignated by the reference numeral and is shown in coaction with avalve 11. The rocker arm and valve assembly may be of any suitableconventional construction in which motion is imparted to the valve by animpact force exerted against the end of the valve stem 12. As is knownsuch motion, in the cycle of an engine, is imparted 'to the valve by therocker arm 10 for unseating or opening the valve 11.

The valve 11 may be made of any suitable metal, although excellentresults may be obtained in engines such as aircraft engines by makingthe valve of an austenitic nickelbase alloy. Desirable results may beattained by the use of an alloy of the following composition:

Chromium 15-17. Titanium 2.75-3.35. Manganese 2.110 2.5. Iron Smax.Carbon .07 max. Silicon .15 max. Sulphur .01 max. Aluminum .1 max.Copper .2 max. Nickel Balance.

Chromium 28.0-32.0. Tungsten l1.014.0. Carbon Q. 2.603.0. Nickel 3.0max. Iron 3.0 max. Silicon 1.5 max. Manganese 1.0 max. Molybdenum 1.0max. Other impurities, total 1.0 max. Cobalt Remainder.

The metal for the insert may be obtained in the form of cast rod,preferably with surface fins and projections removed by grinding. Thematerial of the rod should demonstrate good weldability and shall flowsmoothly and evenly under inert gas shielded are or oxy-acetylenewelding without bubbling or boiling so as to produce an adherent depositfree from porosity. and when molten, shall have sufiicient surfacetension to permit ease of build-up of the deposit.

In addition, the material after being welded or fused as contemplatedand after grinding should have a hardness of 50 to 55 on a Rockwell Cscale.

In the formation of the insert 14 in the stem 12 from the alloy rodstock (not shown), any suitable inert gas shielded are or oxy-acetylenewelding equipment may be used. it will be appreciated that the stem isdisposed with its recessed end uppermost. Then the alloy metal rod isdisposed in the recess 13 and is rendered molten by welding andprogressively puddled in the recess'until the desired depth of insert 14is provided. It has been found that the insert should be of the order of/s inch at the wearer impact point to preclude deleterious dilution ofthe stem metal into thealloy such as would soften the alloy. In thismanner, the metal is puddled in and fused to the end of the stern.

Thereafter any suitable equipment may be employed for fiat grinding theexposed surface of the insert or nubbin 14. It will be observed thatthis insert or nubbin 14 is bodily disposed substantially within theconfines of the length of the stem. This is to be distinguished fromprevious practices of merely butt Welding a tip on a stem.

As an alternative, the metal of the insert may be puddled and bonded instriated or laminated form as indicated at 14 in Fig. 3. This modifiedform of insert 14' is composed of a series of layers of laminations 15superimposed one upon the other in the recess 13 at the end of the valvestem 12. By virtue of the laminations in the modification the outersuccessively puddled and welded laminations would not be affected bydilution of valve stem metal since they are bonded to the metal of theinitial or first lamination.

In both forms the insert 14-44 by virtue of its alloy and the fact thatit has a Rockwell C hardness of the order of 50 will reduce to anegligible minimum manufacturing rejects as compared to rejects of asmuch as 50% in previous practices. In addition, not only is a better andstronger bonding of the insert made possible by virtue of it beingpuddled in the recess, but in addibottom of arcuate contour with asubstantially deep maximum depth along the axis of the stem and with aminimum depth adjacent the circumference of the stem, and said insertnubbin being a solidified puddle with a junction bond along the entireextent of said arcuate bottom and having a substantially flat outer faceforming a wearresisting impact surface, the Wear-resistant surface ofsaid nubbin being substantially undiluted with stem metal, and the bondbetween the nubbin and dished end of the stem extending into both thenubbin and stem metals.

2. An internal combustion engine poppet valve especially adapted foraircraft engines which comprises a valve body having a stem with stemmetal forming a closed solid stem end, the solid end of said stem havinga deeply dished recess in the end face thereof with a maximum depth atthe axis of the valve stem and a minimum depth adjacent thecircumference of the valve stem, a solidified puddle of high carboncobalt base alloy bodily disposed within the confines of the length ofthe stem in said recess in integral relation With the stem metalthroughout a bond area extending substantially into both the stem metaland the puddle metal along the entire contour of the recess, said nubbinhaving a substantially flat outer impact face adapted to resist wear,and the metal constituting said face being substantially undiluted bystem metal.

References Cited in the file of this patent UNITED STATES PATENTS1,526,385 Smith Feb. 17, 1925 1,628,911 Rich May 17, 1927 1,699,273Bissell Jan. 15, 1929 1,823,452 Heron Sept. 15, 1931 1,823,454 JardineSept. 15, 1931 1,889,916 Colwell Dec. 6, 1932 1,904,430 Ferrando et alApr. 18, 1933 2,089,749 Jardine Aug. 10, 1937 2,280,758 Voorhies Apr.21, 1942 2,407,561 Lincoln Sept. 10, 1946 FOREIGN PATENTS 431,547 GreatBritain July 10, 1935

1. AN INTERNAL COMBUSTION ENGINE POPPET VALVE HAVING A METAL STEM WITHMETAL CLOSING THE END OF THE STEM AND FORMING A SOLID DISHED IMPACT ENDPROVIDNG A RECESS WITHIN THE CIRCUMFERENCE OF THE STEM, A HIGH CARBONCOBALT BASE ALLOY INSERT NUBBIN OF HARDER CHARACTERISTIC THAN THE STEMMETAL INTEGRALLY UNITED TO THE STEM THROUGHOUT THE ENTIRE AREA OF SAIDDISHED END, SAID DISHED END HAVING A BOTTOM OF ARCUATE CONTOUR WITH ASUBSTANTIALLY DEEP MAXIMUM DEPTH ALONG THE AXIS OF THE STEM AND WITH AMINIMUM DEPTH ADJACENT THE CIRCUMFERENCE OF THE STEM, AND SAID INSERTNUBBIN BEING A SOLIDIFIED PUDDLE WITH A JUNCTION BOND ALONG THE ENTIREEXTENT OF SAID ARCUATE BOTTOM AND HAVING A SUBSTANTIALLY FLAT OUTER FACEFORMING A WEARRESISTING IMPACT SURFACE, THE WEAR-RESISTANT SURFACE OFSAID NUBBIN BEING SUBSTANTIALLY UNDILUTED WITH STEM METAL, AND THE BONDBETWEEN THE NUBBIN AND DISHED END OF THE STEM EXTENDING INTO BOTH THENUBBIN AND STEM METALS.